Mezzapelle was inspired to write this book series based on his life's experiences, his own contagious optimism, and the encouragement of his Alma Mater, Fairfield University in Connecticut. Book royalties are pledged to the school along with other charities he supports.

Mezzapelle was the founder and director of marketing for Goliath Technology from 1990 - 2007, a data center infrastructure company that supported enterprises worldwide. In addition, Mezzapelle orchestrated an innovative internship program which has become a staple for many organizations today. Prior to 1990 Mezzapelle was employed by IBM.

Goliath Technology was sold in 2007 and Mezzapelle pursued the next level of his passion, building employment tools for schools, students and alumni via GoliathJobs, a marketing and consulting organization he created in 2006 and retained after the sale of his company. GoliathJobs is now an academic arm of Indeed.com.

In 2009, Mezzapelle's holding company, Goliath LLC, formed a joint venture with SilverCensus and Mezzapelle became their marketing & development advisor. Within one year the new SilverCensus grew from a Florida-based directory to a leading senior living and health services resource in the U.S. under his guidance. Today, Mezzapelle consults on various projects and serves on several boards and philanthropic initiatives. Mezzapelle also launched Crane Reed Properties and Goliath Development; organizations that focus on real estate and real estate portfolio management.

Throughout his life Mezzapelle has encountered great peaks and valleys, all of which he is grateful for. He never lost sight along the way and has kept his glass "completely full." He has influenced many people with his outlook and Contagious Optimism is his way of offering optimism to others.

David Mezzapelle believes that we all have the capacity to make optimism contagious just by sharing our life's adventures. Mezzapelle is the founder of the Contagious Optimism movement and the author of Contagious Optimism, a bestselling book series that contains real stories from real people around the globe which demonstrates that every cloud has a silver lining.